Daijiworld Media Network - New Delhi

New Delhi, May 3: A groundbreaking clinical trial has shown that CRISPR/Cas9 gene-editing could become a powerful new weapon against advanced colorectal cancer. Published in The Lancet Oncology, the study marks the first time this technology has been used in humans to engineer immune cells to fight metastatic gastrointestinal (GI) cancers.

Researchers focused on enhancing tumour-infiltrating lymphocytes (TILs)—a type of immune cell—by removing a gene called CISH, which normally limits the T cells’ ability to attack cancer. By disabling this gene using CRISPR/Cas9, the modified cells were able to more effectively identify and destroy cancerous cells.

"Stage IV colorectal cancer continues to be extremely difficult to treat," said Dr. Emil Lou, gastrointestinal oncologist at the University of Minnesota Medical School. "This study brings a novel method of immune enhancement directly to the clinic."

According to Associate Professor Branden Moriarity, traditional drugs can't target CISH because it operates inside the cell, making gene-editing the only viable approach.

The treatment was administered to 12 patients with late-stage, treatment-resistant cancers. It was generally well-tolerated, with no serious side effects directly attributed to the gene-editing process. Notably, several participants experienced halted tumour progression, and one individual had a complete response—his cancer disappeared and stayed gone for over two years.

Unlike conventional treatments that require repeat doses, this CRISPR-based therapy rewires the immune cells permanently from the outset.

"This represents a major leap in how we might treat aggressive cancers in the future," Lou noted. "The ability to manufacture over 10 billion engineered TILs without compromising safety or scale is something we've never achieved before."

However, researchers caution that despite the promising outcomes, the technique remains expensive and complex. Further studies are needed to understand why the therapy worked exceptionally well in certain cases.